Title

The Effect of Yeast Strain on Bread Weight and Acidity

School Name

Spring Valley High School

Grade Level

10th Grade

Presentation Topic

Microbiology

Presentation Type

Non-Mentored

Oral Presentation Award

2nd Place

Abstract

The purpose of this experiment was to determine if yeast strain affected bread qualities. This was done by preparing bread with four kinds of yeast: Saccharomyces cerevisiae, Saccharomyces banavus, Saccharomyces uvaruium, and Saccharomyces boulardii. It was hypothesized that bread containing S. cerevisiae would have the lowest weight and highest pH. To test this hypothesis, bread was prepared four times, each with a different yeast strain, with 30 trials for each. Dough proofed for four hours and was then baked. After baking for 15 minutes the bread was removed from the oven and rested for five minutes. After resting, the bread was removed from the tin and mass was measured. Each piece of bread was then individually blended with 100 mL of water and pH was recorded using an electronic pH meter. The hypothesis was partially disproven. The bread containing S. banavus had the lowest weight. The bread containing S. cerevisiae had the highest pH. An ANOVA of the mass data showed significant differences between the average mass of the bread trials, with a p-value less than 0.0005. Post-hoc testing showed significant differences between all but the bread masses containing S. cerevisiae and S. uvaruium with a p-value of 0.08501. An ANOVA of the pH data showed significant differences between the average bread pH with a p-value less than 0.0005. Post-hoc testing showed significant differences comparing each average to the others. Further testing is required to determine optimal yeast to use when baking bread.

Location

Founders Hall 216 B

Start Date

3-30-2019 8:30 AM

Presentation Format

Oral Only

Group Project

No

COinS
 
Mar 30th, 8:30 AM

The Effect of Yeast Strain on Bread Weight and Acidity

Founders Hall 216 B

The purpose of this experiment was to determine if yeast strain affected bread qualities. This was done by preparing bread with four kinds of yeast: Saccharomyces cerevisiae, Saccharomyces banavus, Saccharomyces uvaruium, and Saccharomyces boulardii. It was hypothesized that bread containing S. cerevisiae would have the lowest weight and highest pH. To test this hypothesis, bread was prepared four times, each with a different yeast strain, with 30 trials for each. Dough proofed for four hours and was then baked. After baking for 15 minutes the bread was removed from the oven and rested for five minutes. After resting, the bread was removed from the tin and mass was measured. Each piece of bread was then individually blended with 100 mL of water and pH was recorded using an electronic pH meter. The hypothesis was partially disproven. The bread containing S. banavus had the lowest weight. The bread containing S. cerevisiae had the highest pH. An ANOVA of the mass data showed significant differences between the average mass of the bread trials, with a p-value less than 0.0005. Post-hoc testing showed significant differences between all but the bread masses containing S. cerevisiae and S. uvaruium with a p-value of 0.08501. An ANOVA of the pH data showed significant differences between the average bread pH with a p-value less than 0.0005. Post-hoc testing showed significant differences comparing each average to the others. Further testing is required to determine optimal yeast to use when baking bread.